As the earth's surface warms, heat-related illness (HRI) is emerging as a serious threat to public health. Certain occupational groups are at an increased risk for HRI, including agricultural workers. Routine work in these hazardous occupational settings without adequate respite may lead to progression down the HRI cascade, ranging from heat cramps to multi-organ failure in extreme cases. Some subpopulations of agricultural workers are at particular high risk if excessively high levels of humidity and low airflow characterize their work environments, circumventing the body's traditional heat regulatory mechanisms. These work conditions challenge the body's capacity to adapt and may lead to more rapid progression down the HRI cascade, potentiating the risk of heat-related morbidity and mortality. The goal of this exploratory research is to characterize the work environment of agricultural workers in the state of Florida and explore the relationships between personal factors and physiologic responses to heat stress in their work environment. A total of 60 Spanish-speaking, agricultural workers in Central Florida will be recruited to 1) characterize the occupational environment of these workers 2) characterize their physiologic responses to heat stress; 3) document self-reported HRI symptoms; and 4) assess work practices and work intensity. Three types of agricultural workers will be sampled: 1) fernery workers, 2) crop workers, and 3) nursery workers. It is hypothesized that fernery workers who are protected from direct sun, but who experience a hot, high humidity environment will have higher levels of uncompensated heat stress when compared to workers in nursery operations or in open crop fields. Knowledge about agricultural work practices, individual risk factors and physiologic responses to work in hazardous extreme heat environments will help direct heat prevention strategies and decrease heat-related health disparities in this vulnerable population. Results from this study will also expand HRI knowledge and contribute to interventions for other vulnerable working populations.